class_docstr: This class handles iteration events to store the current performance as
  an attribute of the sender (i.e. application).
code: def __init__(self, **_unused):
      ITER_FINISHED.connect(self.check_criteria)
  
file_path: NiftyNet/niftynet/engine/handler_early_stopping.py
imports: import numpy
  import tensorflow
  from scipy.ndimage import median_filter
  from niftynet.engine.signal import ITER_FINISHED
label_desc: Use image node_id 1 to create a new EarlyStopper object from inherited base classes: object with example: obj = EarlyStopper()